@@ -0,0 +1,19 @@
+---
+'@objectstack/rest': patch
+---
+
+fix(rest)!: both import doors answer for the object as the data door does — the synchronous import refuses an unregistered object 404, and a legacy short name is the object behind it at every door (#27728, #27729)
+
+Clause-②: no (narrowing) — `POST /data/:object/import` no longer answers 200 for an unregistered object or an object of a disabled package; it answers the data door's 404. And on every `/data/:object` route, a legacy `ns__short` object addressed by its short name is now held to its own `enable` settings (404 or 405). No value, key or shape is added.
+Metadata-protocol: none
+
+<!-- adr-0087: not-required (no-migration-prescription) No key of any schema is added, removed, renamed or re-shaped, and no export or type changes: two already-published refusals (404 OBJECT_NOT_FOUND, 404 OBJECT_PACKAGE_DISABLED) are now answered up front by one more door, and the exposure gate judges the object a short name resolves to. There is nothing for a migration to rewrite and no tombstone. -->
+
+**BREAKING** the synchronous import door refuses what it used to accept with a 200, and the API-exposure gate of every `/data/:object` route now judges a legacy `ns__short` object addressed by its short name (`@objectstack/rest`), per triage 6509235875 (#27728) and 6509225810 (#27729).
+
+- **Before.** `POST /data/:object/import` ran no existence check. For a name with no object behind it, it answered 200 and repeated `OBJECT_NOT_FOUND` inside every row's result; for an object of a disabled package it did the same with `OBJECT_PACKAGE_DISABLED`. An importer that reads the status saw success.
+- **Now.** It answers the data door's own refusal for the name, status and body: 404 `OBJECT_NOT_FOUND`, or 404 `OBJECT_PACKAGE_DISABLED`. It is asked after the API-exposure gate (so a hidden object keeps its 404 and the door is no existence oracle) and before the body is parsed, so nothing is written, dry run included. The async job door (`POST /data/:object/import/jobs`) already refused both; its disabled-package refusal is now pinned with zero job rows.
+- **One read for existence and exposure.** A legacy `ns__short` object addressed by its short name is the object behind that name at every door, as `registry.getObject` resolves it for the data door. The async job door used to refuse such a name `OBJECT_NOT_FOUND` while the data door served it; it now creates the job. The API-exposure gate used to treat such a name as "no object" and pass it on, so an `ns__short` object with `enable.apiEnabled: false` or an `enable.apiMethods` list was served under its short name; the gate now judges that object's `enable` and refuses the same way it refuses the full name. No shipped object carries a `__` name.
+- **Who sees it.** A client that imports into a misspelled or unregistered object name, or into an object of a disabled package, now gets a 404 instead of a 200 with per-row errors. A client that addresses a legacy `ns__short` object by its short name on any `/data/:object` route, where that object sets `enable.apiEnabled: false` or an `enable.apiMethods` list that leaves the operation out, now gets that object's 404 `OBJECT_API_DISABLED` or 405 `OBJECT_API_METHOD_NOT_ALLOWED`, which it already got under the full name.
+
+**The remedy.** Import into a registered object name (or re-enable the package). A client that already read the per-row `OBJECT_NOT_FOUND` should read the response status and `code` instead. For a restricted `ns__short` object, the short name now answers as the full name does: lift the object's `enable` restriction if the API should serve it.
@@ -319,21 +319,26 @@ function importUndoFailure(id: string, action: ImportUndoFailure['action'], erro
 }
 
 /**
- * [#27501] Refuse an import job for an object nothing is behind, with the data
- * door's own answer for that name: `objectNotFoundError` (`@objectstack/core`),
- * the one factory the protocol's existence gate and the engine's verbs throw,
- * classified by the same `handleRouteError` — 404 `OBJECT_NOT_FOUND`, the same
- * envelope `POST /data/OBJ` answers.
+ * [#27501, #27728] Refuse an import for an object nothing is behind, with the
+ * data door's own answer for that name: `objectNotFoundError`
+ * (`@objectstack/core`), the one factory the protocol's existence gate and the
+ * engine's verbs throw, classified by the same `handleRouteError` — 404
+ * `OBJECT_NOT_FOUND`, the same envelope `POST /data/OBJ` answers. Both import
+ * doors ask it, the synchronous one (`POST /data/OBJ/import`) and the job door
+ * (`POST /data/OBJ/import/jobs`), right after the exposure gate and before the
+ * body is parsed, so a refused request writes no row and no job.
  *
  * The object is read by name as the exposure gate reads it (the execution face
- * where the protocol has one, else `getMetaItem`), and counts only under its
- * own name. A read the protocol refuses `OBJECT_PACKAGE_DISABLED` (its
- * by-name read's answer for an object of a disabled package, and the data
- * door's code for it too) propagates as thrown. Any other thrown read fails
- * OPEN and logs, as the exposure gate's same read does (`loadObjectItem`,
- * #3545): it is no answer about existence, and each row's data call still
- * gives the data door's own. A protocol with no by-name read cannot answer,
- * and is not asked.
+ * where the protocol has one, else `getMetaItem`). [#27729] Whatever item that
+ * read serves counts, under whichever name it carries: the by-name read
+ * resolves a legacy `ns__short` object from its short name exactly as the data
+ * door's `registry.getObject` does, so this answer is the data door's for every
+ * name. A read the protocol refuses `OBJECT_PACKAGE_DISABLED` (its by-name
+ * read's answer for an object of a disabled package, and the data door's code
+ * for it too) propagates as thrown. Any other thrown read fails OPEN and logs,
+ * as the exposure gate's same read does (`loadObjectItem`, #3545): it is no
+ * answer about existence, and each row's data call still gives the data door's
+ * own. A protocol with no by-name read cannot answer, and is not asked.
  */
 async function assertImportObjectExists(p: any, objectName: string, environmentId: string | undefined): Promise<void> {
     const byName = typeof p.getMetaItemForExecution === 'function'
@@ -345,12 +350,12 @@ async function assertImportObjectExists(p: any, objectName: string, environmentI
         envelope = await byName.call(p, { type: 'object', name: objectName, ...(environmentId ? { environmentId } : {}) });
     } catch (err) {
         if ((err as { code?: unknown } | null)?.code === 'OBJECT_PACKAGE_DISABLED') throw err;
-        logWarn('[REST] import job: object metadata read failed — not refused up front '
+        logWarn('[REST] import: object metadata read failed — not refused up front '
             + '(each row\'s data call still answers for the object)', (err as Error)?.message ?? err);
         return;
     }
     const item = envelope?.item;
-    if (item !== null && typeof item === 'object' && item.name === objectName) return;
+    if (item !== null && typeof item === 'object') return;
     throw objectNotFoundError(objectName);
 }
 
@@ -517,6 +522,14 @@ export function registerDataActionEndpoints(this: DataActionRouteHost, basePath:
                     return;
                 }
                 if (await this.enforceApiAccess(req, res, p, environmentId, 'import', context)) return;
+
+                // [#27728] The object must exist before any row is read. The
+                // exposure gate above passes an unknown object through by design
+                // (#3770), and the data door's existence refusal used to fire only
+                // inside each row's write, so a misspelled name answered 200 with
+                // every row refused. Refused here, with the data door's answer.
+                await assertImportObjectExists(p, objectName, environmentId);
+
                 const body = req.body ?? {};
 
                 // [#24348] Who may take the object's declared controls off this
 
@@ -0,0 +1,218 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * [#27728, #27729] Both import doors answer for the object exactly as the data
+ * door does (`POST /data/:object`), before any row or job is written:
+ *
+ *  - the synchronous door (`POST /data/:object/import`) refuses an unregistered
+ *    object with the data door's 404 `OBJECT_NOT_FOUND`, where it used to answer
+ *    200 with the refusal repeated inside every row's result (#27728);
+ *  - both doors refuse an object of a DISABLED package with the data door's
+ *    404 `OBJECT_PACKAGE_DISABLED`, status and body, and write no row and no
+ *    `sys_import_job` row (#27729 item 1);
+ *  - a legacy `ns__short` object addressed by its short name is the object
+ *    behind that name at every door: the existence read and the API-exposure
+ *    gate both take the item the by-name read resolves, as the data door's
+ *    `registry.getObject` does, so the job door no longer refuses a name the
+ *    data door serves, and the gate judges that object's `enable` instead of
+ *    passing the short name through (#27729 item 2).
+ *
+ * A REAL `ObjectQL` engine + `ObjectStackProtocolImplementation` on a REAL
+ * sqlite `:memory:` driver; nothing below the routes is a double.
+ */
+
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { ObjectQL } from '@objectstack/objectql';
+import { SqlDriver } from '@objectstack/driver-sql';
+import { ObjectStackProtocolImplementation } from '@objectstack/metadata-protocol';
+import { SysMetadataAuditObject, SysMetadataCommitObject, SysMetadataHistoryObject, SysMetadataObject } from '@objectstack/metadata-core';
+import { SysImportJob } from '@objectstack/platform-objects/audit';
+import { RestServer } from './rest-server';
+import { installDefaultOrganization } from './default-organization.testkit.js';
+
+const liveEngines: ObjectQL[] = [];
+afterEach(async () => {
+  while (liveEngines.length) {
+    try { await liveEngines.pop()?.destroy(); } catch { /* noop */ }
+  }
+});
+
+const fields = {
+  id: { name: 'id', type: 'text' as const, primaryKey: true, label: 'ID' },
+  title: { name: 'title', type: 'text' as const, label: 'Title' },
+};
+
+/** A plain object, the control. */
+const TASK = { name: 'ex_task', label: 'Task', systemFields: false, fields };
+/** An object of a package the test disables. */
+const OFF_PACKAGE = 'app.ex_off';
+const GADGET = { name: 'ex_gadget', label: 'Gadget', systemFields: false, fields };
+/** Legacy `ns__short` objects, addressed below by their short names. */
+const LEGACY_PACKAGE = 'app.ex_legacy';
+const WIDGET = { name: 'exl__widget', label: 'Widget', systemFields: false, fields };
+const VAULT = { name: 'exl__vault', label: 'Vault', systemFields: false, enable: { apiEnabled: false }, fields };
+
+function makeRes() {
+  const res: any = {
+    write: () => true, end: () => {},
+    header: () => res,
+    status: (code: number) => { res._status = code; return res; },
+    json: (body: any) => { res._json = body; return res; },
+  };
+  return res;
+}
+
+async function boot() {
+  const engine = new ObjectQL();
+  liveEngines.push(engine);
+  engine.registerDriver(new SqlDriver({ client: 'better-sqlite3', connection: { filename: ':memory:' }, useNullAsDefault: true }), true);
+  await engine.init();
+  engine.registry.installPackage({ id: OFF_PACKAGE, name: OFF_PACKAGE, version: '1.0.0' } as any, 'code');
+  engine.registry.installPackage({ id: LEGACY_PACKAGE, name: LEGACY_PACKAGE, version: '1.0.0' } as any, 'code');
+  engine.registry.registerObject(TASK as any);
+  engine.registry.registerObject(GADGET as any, OFF_PACKAGE);
+  engine.registry.registerObject(WIDGET as any, LEGACY_PACKAGE);
+  engine.registry.registerObject(VAULT as any, LEGACY_PACKAGE);
+  engine.registry.registerObject(SysImportJob as any);
+  await engine.syncSchemas();
+  // A real `single` install's Default Organization (ADR-0131 D9).
+  await installDefaultOrganization(engine);
+  for (const o of [SysMetadataObject, SysMetadataHistoryObject, SysMetadataAuditObject, SysMetadataCommitObject]) {
+    if (!engine.registry.getObject(o.name)) engine.registry.registerObject(o as any);
+  }
+
+  const protocol = new ObjectStackProtocolImplementation(engine as any);
+  const noop = () => {};
+  const server = { get: noop, post: noop, put: noop, delete: noop, patch: noop, use: noop, listen: async () => {}, close: async () => {} };
+  const rest = new RestServer(server as any, protocol as any, { api: { requireAuth: false } } as any);
+  (rest as any).resolveExecCtx = async () => ({ userId: 'test-user' });
+  rest.registerRoutes();
+  const routes = rest.getRoutes();
+  const route = (path: string): any => {
+    const found = routes.find((r: any) => r.method === 'POST' && r.path === path);
+    if (!found) throw new Error(`route POST ${path} is not registered`);
+    return found;
+  };
+  const doors = {
+    data: route('/api/v1/data/:object'),
+    sync: route('/api/v1/data/:object/import'),
+    jobs: route('/api/v1/data/:object/import/jobs'),
+  };
+  return {
+    engine,
+    async call(door: keyof typeof doors, object: string, body: any) {
+      const res = makeRes();
+      await doors[door].handler({ params: { object }, body, query: {} } as any, res);
+      // The synchronous door answers with `res.json` alone on success.
+      return { status: res._status ?? 200, body: res._json };
+    },
+    /** Rows of a table, counted at the engine. */
+    async count(table: string) {
+      const rows = await engine.find(table, { where: {} });
+      return Array.isArray(rows) ? rows.length : 0;
+    },
+  };
+}
+
+const rowsBody = (id: string) => ({ format: 'json', rows: [{ id, title: 'x' }] });
+
+describe('[#27728] the synchronous import door refuses an unregistered object as the data door does', () => {
+  let h: Awaited<ReturnType<typeof boot>>;
+  beforeEach(async () => { h = await boot(); });
+
+  it('answers 404 OBJECT_NOT_FOUND, the data door\'s envelope byte for byte, not 200', async () => {
+    const door = await h.call('data', 'ex_no_such_object', { id: 'n1', title: 'x' });
+    expect(door.status).toBe(404);
+    expect(door.body?.code).toBe('OBJECT_NOT_FOUND');
+
+    const sync = await h.call('sync', 'ex_no_such_object', rowsBody('n2'));
+    expect(sync.status).toBe(404);
+    expect(sync.body).toEqual(door.body);
+  });
+
+  it('a dry run and a CSV body get the same refusal, before the body is parsed', async () => {
+    const door = await h.call('data', 'ex_no_such_object', { id: 'n1', title: 'x' });
+    const dry = await h.call('sync', 'ex_no_such_object', { ...rowsBody('n3'), dryRun: true });
+    expect(dry).toEqual({ status: 404, body: door.body });
+    // Not even a parseable body is needed: the object is asked first.
+    const csv = await h.call('sync', 'ex_no_such_object', { format: 'csv', csv: 'not,a\n"broken' });
+    expect(csv).toEqual({ status: 404, body: door.body });
+  });
+
+  it('control: a registered object still imports (200, one row created)', async () => {
+    const sync = await h.call('sync', 'ex_task', rowsBody('t1'));
+    expect(sync.status).toBe(200);
+    expect(sync.body).toMatchObject({ object: 'ex_task', total: 1, ok: 1, created: 1, errors: 0 });
+    expect(await h.count('ex_task')).toBe(1);
+  });
+});
+
+describe('[#27729 item 1] both import doors refuse a disabled package\'s object with the data door\'s answer', () => {
+  let h: Awaited<ReturnType<typeof boot>>;
+  beforeEach(async () => {
+    h = await boot();
+    h.engine.registry.disablePackage(OFF_PACKAGE);
+  });
+
+  it('the data door\'s answer is 404 OBJECT_PACKAGE_DISABLED (the reference)', async () => {
+    const door = await h.call('data', 'ex_gadget', { id: 'g0', title: 'x' });
+    expect(door.status).toBe(404);
+    expect(door.body?.code).toBe('OBJECT_PACKAGE_DISABLED');
+  });
+
+  for (const kind of ['sync', 'jobs'] as const) {
+    it(`${kind}: status and body equal the data door's, and no row and no job row is written`, async () => {
+      const door = await h.call('data', 'ex_gadget', { id: 'g0', title: 'x' });
+      const answer = await h.call(kind, 'ex_gadget', rowsBody('g1'));
+      expect(answer.status).toBe(door.status);
+      expect(answer.body).toEqual(door.body);
+      expect(await h.count('sys_import_job')).toBe(0);
+      expect(await h.count('ex_gadget')).toBe(0);
+    });
+  }
+});
+
+describe('[#27729 item 2] a legacy ns__short object is the object behind its short name at every door', () => {
+  let h: Awaited<ReturnType<typeof boot>>;
+  beforeEach(async () => { h = await boot(); });
+
+  it('premise: the data door serves the short name (registry.getObject resolves it)', async () => {
+    expect((h.engine.registry.getObject('widget') as any)?.name).toBe('exl__widget');
+    const door = await h.call('data', 'widget', { id: 'w0', title: 'x' });
+    expect(door.status).toBe(201);
+  });
+
+  it('the job door creates the job, where it used to answer OBJECT_NOT_FOUND', async () => {
+    const jobs = await h.call('jobs', 'widget', rowsBody('w1'));
+    expect(jobs.status).toBe(201);
+    expect(jobs.body).toMatchObject({ object: 'widget', status: 'pending', total: 1 });
+    expect(await h.count('sys_import_job')).toBe(1);
+  });
+
+  it('the synchronous door imports under the short name', async () => {
+    const sync = await h.call('sync', 'widget', rowsBody('w2'));
+    expect(sync.status).toBe(200);
+    expect(sync.body).toMatchObject({ object: 'widget', ok: 1, created: 1 });
+  });
+
+  it('an unregistered short name is still OBJECT_NOT_FOUND at both import doors', async () => {
+    const door = await h.call('data', 'gizmo', { id: 'z0', title: 'x' });
+    expect(door.status).toBe(404);
+    expect(await h.call('sync', 'gizmo', rowsBody('z1'))).toEqual(door);
+    expect(await h.call('jobs', 'gizmo', rowsBody('z2'))).toEqual(door);
+    expect(await h.count('sys_import_job')).toBe(0);
+  });
+
+  it('the exposure gate judges the resolved object: apiEnabled:false hides it under its short name too', async () => {
+    const full = await h.call('data', 'exl__vault', { id: 'v0', title: 'x' });
+    expect(full.status).toBe(404);
+    expect(full.body?.code).toBe('OBJECT_API_DISABLED');
+    for (const kind of ['data', 'sync', 'jobs'] as const) {
+      const short = await h.call(kind, 'vault', kind === 'data' ? { id: 'v1', title: 'x' } : rowsBody('v1'));
+      expect(short.status).toBe(404);
+      expect(short.body?.code).toBe('OBJECT_API_DISABLED');
+    }
+    expect(await h.count('exl__vault')).toBe(0);
+    expect(await h.count('sys_import_job')).toBe(0);
+  });
+});